What is Brain Stem Glioma?

Brain stem gliomas are a group of tumours located in the area of the brain called the brainstem. These account for 10-20% of brain tumours in childhood, and commonly affect children between the ages of 5 to 10. They can be of a low or high-grade, however a larger number (approximately 70%) are high-grade.

The brainstem is the area at the lower back portion of the neck, which connects the spinal cord with the brain. It is the area of the brain and spinal cord that is responsible for many vital body functions, including vision, swallowing, gagging, balance and strength. Because of the location of these tumours, they are more difficult to treat than gliomas in other parts of the brain.

Low-grade brain stem gliomas are focal, or confined to one area of the brain stem. High-grade brain stem gliomas tend to be diffuse, or infiltrate and spread throughout the brain stem.

Signs & Symptoms

Children with a low-grade brain stem glioma commonly present with a long history (greater than 6 months) of symptoms, including headaches, vomiting and visual disturbances.

Children presenting with a high-grade tumour experience similar symptoms, however the onset of symptoms is generally more sudden or acute.

Treatment

Low-grade brain stem gliomas

Although these tumours arise in a vital area of the brain, the Neurosurgeon may partially or incompletely remove them. This is because they are generally contained to one area of the brainstem, and when surgically approached, is not life threatening. Additional treatment (ie, chemotherapy and/or radiotherapy) following surgery is often not required. Chemotherapy may be necessary in children whose tumour progress following surgery, or whose tumours were not surgically accessible.

High-grade brain stem gliomas

A surgical resection is not usually an option for treatment of a high-grade brain stem glioma. This is because of the tumour's location within the brain stem, which is diffuse and infiltrating. This can lead to damage to the nerves within the brain stem that are vital for breathing, swallowing, consciousness, arm, leg and eye movement. A biopsy is rarely performed for similar reasons, therefore diagnosis is often made on clinical presentation of the child and neuro-imaging (CT scans and MRI scans).

Radiation treatment to the area of the tumour is the current standard of treatment for this tumour type. A large percentage of children will clinically improve with radiation treatment, but their condition will decline rapidly within 6-9 months after completing therapy. There is currently no clear role for chemotherapy in the treatment of these tumours.

Other issues

Approximately 50% of children with brain stem gliomas will develop hydrocephalus at some stage during the course of their illness. Hydrocephalus is a build up of fluid within the brain, caused by obstruction of the normal cerebrospinal fluid (fluid that surrounds the brain and spine) pathway by the tumour. Insertion a shunt system (ventriculo-peritoneal shunt) is necessary to treat this condition. Children with brain stem gliomas are often prescribed steroids because of the swelling and tightness the tumour causes at the base of the skull. Because of the side effects of steroids, including mood changes, weight gain and fluid retention, steroids are used sparingly.

Follow Up Care

After treatment has finished, children visit clinic on a regular basis, and undergo MRI scans to monitor the state of their disease